Rotary kiln.



W, D. MOUNT.

v ROTARY KILN.

APPLICATION FILED IAN. II. I916.

l, 1'79,952 Patented Ap1-.`18,1916.

2 SHEETS-SHEET I.

W. D. MOUNT. ROTARY KILN. APPLICATION FILED 1AN.11.1915.

Patented Apr. 18,1916.

2 SHEETS-SHEET 2- IIII llllllllll l UNHED STATE@ PATENT @FETCH WILLIAM ID. MOUNT, OF SALTVILLE, VIRGINIA. ASSIGNOR TO THE MATHIESON ALKALI WORKS, A CORPORATION OF'VIRGINIA.

ROTARY KILN.

Specification of Letters Patent.

Patented Apr. 18, 1916.

Application led January 11, 1916. Serial No. 71,399.

` useful Improvements in Rotary Kilns, of

which the following is a full, clear, and exact description.

This invention relates to rotary kilns which, as is` well known, comprise a long hollow cylinder arranged at a slight incline and provided with means for imparting to the kiln a slow rotary movement; the material to be treated is fed to the kiln at its upper end and comes into intimate Contact with the heated gasesy of combustionwhich pass through. the kiln in the opposite direction. f

Kilns of this general character are in common use, but difficulties have ybeen encountered in their use where the material to be treated is of such a character that it adheres to the walls of the kiln, for the ent-ire surface of the wall soon becomes coated with a layer of the material which increases in thickness as more material is fed to the kiln until the kiln becomes choked. This condition exists in the treatment of many kinds of material, and as an example moist pulverulent lime-stone may be referred to. As is well known, this material is obtained as a ley-product when soda-ash is treated with lime to producefoaustic soda, and is then afterward burned in a rotary kiln to reconvert it into lime when it kmay again be used in the production of more caustic soda. This invention. while primarily designed to overcome'the difliculty referred to in the treatment of this material in 'a rotary kiln, is not limited to it and consists of a rotary kiln having a plurality of dislodging members mounted upon the wall thereof which may be actuated to dislodge the adhering material without stopping of the kiln. Where the material to be treated is such that it is only while it is in moist condition that it adheres to the surface of the lining wall, as in the example cited, then it is only necessary to provide these dislodging members adjacent the feeding zone of the kiln, although they `may be extended the entire lengththereof if desired. In the preferred construction, the dislod gingmemberseach comprises a plunger having a head or plateinset into the kiln so that its surface will be flush' with the surface of the lining wall of the kiln and form a part thereof during normal conditions. The plungers are spring-actuated and have their ends extending exterior-ly of the kiln so that they may be struck as the kiln rotates to force the plunger inwardly and thus cause the material adhering to the wall to be forcibly separated therefrom.

The invention also consists of a plurality of angularly disposed blades or flights mounted on the lining wall and arranged to form a helix which serves as a screw conveyer to feed the material along the kiln. These blades are interposed between the dislodging members or plates in such a manner as to not interfere with the proper actuation of the latter, and in one practical construction, the portion or zone of the kiln which is provided with the dislodging plates or members is composed of a plurality of axially arranged annular rings which form the lining wall, each ring consisting of a plurality of segmental portions which are bolted together. The blades are carried by some lof these segmental pieces and extend diagonally thereacross, the blades of the various rings being arranged in substantially helical form. The remaining segments of each ring carry the dislodging members, which in adjacent rings are disposed in staggered relation so as to insure the complete removal of the substance from the walls.

The invention may also be understood from an illustrated embodiment of the invention taken in connection with the description thereof, and in the accompanying drawings: Figure l is a central section through a kiln constructed in accordance with the principles of my invention, only a sufficient part of the kiln being shown to disclose the invention; Fig. 2 is a development of a section of the feeding end of the kiln; Fig. 3 is a detail of the connection which holds the blades o'r flights in place; Fig. fl is a transverse section on the line 4-4 of Fig. l; and Fig. 5 is a detail of one of the annular rings which form the feeding end of the kiln.

The kiln illustrated consists of a long hollow cylinder which is mounted in any desired manner in a slightly inclined position and is adapted to be rotated by any suitable mechanism, not shown. The feeding zone 1 of this kiln is shown at the left of Fig. 1, and since the kiln is particularly designed for the treatment of moist pulverulent lime-stone and similar material, it is only necessary that the feeding portion of the lining wall of the kiln be provided with dislodging members to prevent it from becoming coated with the material; in the other parts of the kiln, the material is dry and will not stick to the lining walls thereof. rllhe remaining portion of the kiln which has been designated 2 has an intermediate section 'thereof omitted as at 8, so as not to unduly increase the length of the drawing, and is of the usual construction consisting of an outer iron casing 4, and a lining wall 5` of fire brick or other vitreous material, rlhe feeding Zone l yof the kiln, in the rform illustrated is composed of a plurality of annular rings 6 which form the lining-wall and are of the. same internal diameter as the lower part of the kiln being arranged in axial alinement therewith. The rings 6 are secured together by bolts or other fastening devices passing through flanges 7 projecting exteriorly from the peripheral edges of the rings. As will be clear from Fig. 4, each annular ringv ispreferably made in sections, sixrsuch segmental sections being shown and designated 7 to 12respectively, the segmental sections being united by bolts passing through lugs 18 carried by each of the sections. Surrounding the rings 6 is an outer casing 14- which formsa continuation of the outer casing` or shell 4 of the lower part of the kiln. This casing is secured to theendr ring by means of an annular flange or header 15.

Each of the rings 6 hasmounted thereon a plurality of dislodging devices or members and in the form illustrated each of these devicesy is of the same construction and consists of a plunger 15 which has a broad base forming rectangular plate 1G. rfhis plate is inset in a` correspondingly shaped opening in the ring, while surrounding the plunger is a cylinder or sleeve 17 having a curvedy flange or base 18, which is secured to the exterior surface of the ring and against which the base or plate 1G- is adapted to rest in the normal operation of the kiln, the flange 1S being so spaced from the inner surface of the ring 6 that thesurface of the plate 16 will be flush with the inner surface ofthe ring forming the lining wall of the kiln. In other words, during the normal conditions they plates 16 form a part ofthe lining wall of the kiln. The sleeve or cylinder 17v surrounding theplnnger 15 is of a height to fit between the inner ring 6 and the outer casing lll and hence will also serve as a spacing member to maintain the outer casing inposition; Mounted onvthe plunger 15 in axial alinement is a plunger rod 19 which passesV through an opening in the casing 14: and is provided with an enlarged head or knob 20. Surrounding` the plunger rod is a tension spring 21, one end of whichy bears. against the knob 2O and the other against the casing 14 sov that the plunger 15 and its base or plate 16 is normally maintained in a position in which the face plate and lining wall are flush.

In the construction shown, two such dislodging devices or members are mounted upon four of the segments of each annular ring while two oppositely disposed segments carry angularly-disposed blades which form a screw conveyer. The segments which carry the blades are each provided with four openings 2Q, aid-,ranged diagonally across thel flangel and the blades which have been designated 23 are provided with lugs 24 which are adaptedV to pass through these openings. The lugs 24 are provided with square recesses into which two wedge-shaped blocks 26 t, whiley passing through the blocks is a bolt and nut 27 which, when tightened, moves the blocks together and hencedraws the blades into firm engagementI with the wallsof the ring and the blades are rigidly heldin position.

Referring now to Fig. :2, a development of a portion ofthe kiln is illustrated which shows the preferred. arrangement of vthe dislodging members and blades, the plates loof the dislodging members being arranged in staggered relation so as to insure the complete removal of the layer of material which forms on the lining wall, while the blades are arranged in substantially helical form thusy providing a screw conveyer for feeding the mass of material en-` tering through the front end of the kiln to rthe lower part thereof. Y

Theoperation of the kiln is obvious.r Let us assume that the heated gases or products of combustion. pass through the kiln from right to left as shown in F ig. 2, and the material, such as moist pulverulent limestone, is fed into the front end of the kiln. As the kiln revolves, the screw flightv or conveyer formed by the blades willy positively advance the material toward the lower end of the kiln, while at the same time the lime-stone is being acted upon-by the heated gases passing through in the opposite direction to convert the limestone into lime. After the kiln hasbeenfin operation for sometime, a coating of the material will form upon the lining wall composedy of the rings 6. When suchwa layer forms, a workman strikes each knob or head 2O a heavy blow with a Sledge or other implement as thev pass by himin the rotation of the kiln. This blow, forces each plunger radially inwardly and will forcibly separate the material from the wall of the kiln after which the plunger returns to-its normal position in which `it is.y flush with and forms a part of the lining wall of the kiln. The kiln can therefore be operated continuously and the lining walls of the same kept comparatively clean.

In so far as I am aware, it is broadly new with me to provide movable members on the lining wall of a kiln which may be actuated to forcibly separate thema- `terial from the lining wall and it is my intention to cover this feature broadly as will be evidenced by the scope of the claims appended hereto.

y I claim:

l. A rotary kiln having a plurality of movable wall sections forming a part of its lining wall and constituting dislodging members.

2. A rotarykiln having a plurality of inwardly movable dislodging members .mounted on the lining wall thereof.

3. A rotary kiln having a plurality of movable dislodging members mounted on the lining wall thereof, and means for moving said members inwardly.

il. A rotary kiln having a plurality of movable dislodging members mounted on the lining wall thereof, said members each having a part extending exteriorly of the kiln and adapted to be struck to force the dislodging member inwardly.

5. A rotary kiln having a plurality of dislodging members mounted on the lining `wall thereof, each of said members comprising a spring actuated plunger having a part extending exteriorly of the kiln.

6. A rotary kiln having a plurality of dislodging members mounted on the lining wall thereof, each of said members comprising a plunger having a base, the surface of which is iiush with the surface of the lining wall of the kiln.

fr'. A rotary kiln having a plurality of dislodging members mounted on the lining wall thereof, each of said members comprising a plunger having an enlarged base having its surface flush with the lining wall of the kiln, each of said plungers having a part extending exteriorly of the kiln and adapted to be struck to force the plunger inwardly. j

8. A rotary kiln having a plurality of dislodging members mounted on the lining wall thereof, in spaced relation and forming circular rows, the dislodging members in adjacent rows being disposed in staggered relation.

9. A rotary kiln comprising a plurality of axially alined annular rings, the inner surfaces of which form a portion at least of the lining wall of the kiln, a plurality of dislodging members mounted on each of said rings in spaced relation therearound.

10. A rotary kiln comprising a plurality of axially alined rings, the inner surfaces of which form a portion at least of the lining wall of the kiln,'a plurality of dislodging members mounted on the inner surfaces of said rings, said dislodging members having their faces flush with the surfaces of said rings.

1l. A rotary kiln comprising a plurality of axially alined rings, the inner surfaces of which form a portion at least of the lining wall of the kiln, a plurality of dislodging members mounted on the inner surface of each of said rings, each of said dislodging members comprising a plunger having an enlarged base iitting into the recess of the ring, said plunger having a part connected thereto extending exteriorly of the kiln and adapted to be struck to force the plunger inwardly.

12. A rotary kiln comprising a plurality of axially alined rings, the inner surfaces of which form a portion at least of the lining wall of the kiln, each of said rings comprising a plurality of separable segments secured together, dislodging members carried by some of said segments and inwardly projecting blades carried by the other of said segments, said dislodging members of adjacent rings being disposed in staggered relation and said blades on said rings being disposed to substantially form a helix.

13. In a rotary kiln, a plurality of axially alined rings, the inner surfaces of which form a portion at least of the lining wall of the kiln, inwardly projecting segmentalshaped blades carried by each of said rings, dislodging members mounted on the inner surface of each of said rings, and said blades on the rings being disposed in substantially helical form.

14. In a rotary kiln, a plurality of segmental-shaped blades projecting inwardly from the lining wall thereof, said blades being disposed around the lining wall in substantially helical form and a plurality of dislodging members mounted on said lining wall and disposed in staggered relationship.

In witness whereof, I subscribe my signature in the presence of two witnesses.

WILLIAM D. MOUNT.

Witnesses:

NANCY SPENCER, J. A. WATSON.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

